I have never seen a report of anyone climbing over Pinnacle Ridge. Looking at the CalTopo map, I see a "Pinnacle Pass" identified a half mile east of Pinnacle Ridge, but again, never seen a report of anyone going over. The contours look like it may be a possibility, though.
I have personally climbed Thor Pk from a point midway between Lower and Upper Boy Scout lakes, and then descended via Mirror Lk.
But you are planning on an overnight at Trail Camp, so you would need to haul your overnight pack up and over. It might be possible if you go ultralight, and are almost superhuman, since you'd be climbing Russell the same day.
More realistic would be to camp one night at UBSL, climb Russell next day, (maybe spend a second night), then haul your pack over Thor Pk or Pinnacle Pass, and meet your group at Trail Camp. You could maybe find a route over Pinnacle Pass with the pack, and then head west around Wotan's Throne to Trail Camp. Once over Pinnacle Pass, you can definitely hike around Wotan's Throne.
Another option: Climb to Trail Camp with your group, climb Whitney and Muir, then from Trail Camp, split from the group, head north and cross Pinnacle Pass or Thor Pk, descend to Upper Boy Scout, and camp a second night. Climb Russell next day and hike out.